The Appeal CommissionThe Workers Compensation Act of Manitoba

Background

The worker is right-handed. She has been employed with the same employer for over 10 years.

During her employment she has worked as a receptionist and a sales associate as follows: from 1994 to 1996, receptionist; from 1996 – 2000, sales, and from 2001 forward, receptionist.

The worker’s job duties are noted on file. At the hearing, the worker provided additional information as follows:

As a receptionist:

• she works 8 hours a day, 5 days a week;
• she uses the computer to enter reports and credit notes;
• most of the typing is done on a numeric pad using her right hand;
• the typing is not continuous; it is interspersed with telephone calls;
•  she works at a steady pace;
• the busiest week is the fourth week of the month where she may type up to 5 hours in one day. The other weeks she types between 2 and 3 hours per day;
• she types in a wrist-neutral position;
• she answers phones;
• she writes down messages or credit notes with her right hand while holding the phone with her left hand. Her left hand is held in a wrist-neutral position.

As a sales associate:

• she worked 8 hours a day, 5 days a week;
• she used a Telxon machine keying in orders with her right hand;
• the Telxon machine was positioned at a 45˚angle. She would position her elbow on the table with her forearm and hand raised about 45˚. The wrist would have been in a slightly flexed position;
• she answered phones with her left hand using a neutral wrist position;
• 80% of her day consisted in using the Telxon machine;
• she worked at a steady pace.

The worker testified that she first began feeling CTS symptoms while working as a sales associate. The onset was in both hands but she noticed it more in her right hand. Her symptoms remained the same when she left her sales position and started her receptionist position. She did however notice an increase in her symptoms during the day when it was busy or during the nights depending on how she slept. Then over time, her symptoms progressively got worse.

Two medical reports have indirectly commented on the relationship between the worker’s job duties and her bilateral CTS. A June 12, 2003 report from the treating neurologist comments that “she has no contributing avocational activities”. An April 18, 2004 report from her family physician notes that the worker “has a job which involves repeated flexion and extension of hands”.

Worker’s Position

The worker says that her claim is acceptable as her bilateral CTS developed while she worked with this particular employer doing sales and receptionist duties. She says that there is essentially no other explanation for the development of this condition as she does not have any other non-work related risk factors.

Analysis

To accept the worker’s appeal we must find on a balance of probabilities that she suffered a workplace accident within the meaning of subsections 4(1) and 1(1) of The Workers Compensation Act and more particularly that her bilateral CTS is causally related to her work duties. Based on the evidence before us we are unable to make that finding.

Carpal tunnel syndrome is defined as the impairment of the motor and/or sensory function of the median nerve as it traverses through the carpal tunnel.  It is caused either by intrinsic swelling of the median nerve or by extrinsic compression of the median nerve by one of the many surrounding structures of the wrist.  CTS has a variety of causes. It can be caused by underlying systemic conditions such as rheumatoid arthritis, ostearthritis, hypothyroidism, and diabetes. Middle-aged overweight females, smokers and people genetically pre-disposed to the development of CTS are also at increased risk for the development of CTS. It can also be caused by some work activities. As stated by the Review Officer, there remains considerable debate in the medical literature as to what work factors may cause CTS. Occupational factors most commonly accepted to be associated with CTS include a wrist injury, frequent use of vibrating hand tools or any repetitive, forceful motion with the wrist bent, especially when done for prolonged periods without rest. It is generally considered that the greatest frequency of occupationally related CTS is found where job duties involve high force and high repetition.

It is for this reason that the worker’s job duties need to be examined carefully to determine whether on a balance of probabilities they might have caused her bilateral CTS.

In reviewing the evidence before us, we are unable to find a link between her work duties and her CTS. Quite simply there is insufficient evidence that her wrists were maintained in a position or used in a manner that would put her at risk for developing CTS. Indeed, her computer duties done with the right hand are done in a wrist neutral position and are not highly repetitive. Further, her left hand work, as a receptionist and sales associate, are limited to holding the phone in a wrist neutral position. Though there is some evidence that the right wrist might have been more at risk during the sales associate job, several factors weight against linking those duties to her CTS: